Generally, an inductor is a passive electrical component that can store energy in a magnetic field created by an electric current passing through it. An inductor may be constructed as a coil of conductive material wrapped around a core of dielectric or magnetic material. One parameter of an inductor that may be measured is the inductor's ability to store magnetic energy, also known as the inductor's inductance. Another parameter that may be measured is the inductor's Quality (Q) factor. The Q factor of an inductor is a measure of the inductor's efficiency and may be calculated as the ratio of the inductor's inductive reactance to the inductor's resistance at a given frequency.
Inductors may be utilized in a wide variety of applications. One such application of an inductor may be as a choke, in which an inductor is designed to have a high inductive reactance to, or block, signals with certain frequencies in an electrical circuit while allowing passage of other signals at different frequencies in the electrical circuit. A choke may be made, for example to block a radio frequency (RF), and may be called a RF choke, which is of use in radio communications.
Traditionally, the inductance of an inductor may be increased by increasing the number of coils of conductive material around the core. However, increasing the number of coils also increases the resistance, parasitic capacitance, and especially the size of the inductor. This increase in size of the inductor has hindered the placement, use, and miniaturization of inductors onto semiconductor dies. This has also hindered the ability of inductors to be both improved by improving the inductance while also reducing the size of the inductor. As such, what is needed is an increase in an inductor's inductance while maintaining or reducing the size of the inductor and its coils.
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale.